Along with quickly replacement of the information products, the electronic apparatuses with a central processing unit (CPU) as a control center are quickly developed, such as personal computer, notebook, personal digital assistant (PDA) and information appliance (IA). Each of those electronic apparatuses has an operation system to play both roles of an interface between users and the electronic apparatus, and of a manager in the entirety of software and hardware.
When the electronic apparatus enters the operation system after finishing the starting procedure, the system loading will has very big difference because the program or the instruction executed is different. For example, when a personal computer is executing a complicated game program, the system loading of the personal computer is 4 or 5 times of that for executing a general document work. However, the CPU still uses unified and fixed front side BUS frequency to execute different programs and instructions. That is, the CPU uses the same executing speed to deal with different software even thought the software has different degrees in the complication. Hence, if the system mostly deals with the simple program and the system loading is lighter, the fixed executing frequency will cause whole resource-consumption, increase power consumption, and reduce use life of the electronic apparatus.
In addition, the speed step technology is developed by Intel Company to apply in a portable personal computer for detecting whether the power is provided by a power supply or a battery. Then, the CPU will be switched to higher working frequency when using the power supply and to lower working frequency when using the battery for saving the energy resource. However, the CPU still uses the same executing speed to deal with the different complicated programs.
Therefore, the purpose of the present invention is to develop a method and a device to deal with the above situations encountered in the prior art.